Onome Ejeromedoghene,Olayinka Oderinde,Sheriff Adewuyi,Guodong Fu
Recently, the fabrication of functional and stimuli-responsive hydrogels using deep eutectic solvent derivatives is gaining tremendous scientific recognition owing to their unique self-switching properties. In this study, perfluorinated deep eutectic mixtures were prepared as the template for the synthesis of WO 3 /MoO 3 composites. The metal oxide-based composites were further employed as a chemical crosslinking agent for the polymerization of polyvinyl pyrrolidine (PVP) and acrylamide (Am), for the construction of (PVP-Am)/WO 3 /MoO 3 hydrogel composites. The hydrogels displayed unique morphologies and mechanical properties . The hydrophilic nature of hydrogels as well as the high concentration of dispersed WO 3 /MoO 3 composites in the polymer network contributes to their photochromic activity and allows an immediate coloration upon exposure to light at a short time. Howbeit, the low concentration of the dispersed WO 3 /MoO 3 composites in the dry glass membrane is responsible for the blue coloration and an extended time of photochromic response. In addition, the electrochromic behavior of the hydrogel composites displayed a strong quasi-rectangular shape potential window as well as a well-defined redox cyclic voltammetry curve when exposed to high voltage. This could be due to the photoredox property of the WO 3 /MoO 3 composites responsible for charge transfer between the different oxidation states.
Yuxuan Shao,Dan You,Yuqi Wan,Qingrong Cheng,Zhiquan Pan
The activation capacity of molecular oxygen is an important indicator to evaluate the photocatalytic efficiency of a catalyst. In this paper, MoO3−x nanosheets with oxygen vacancies were deposited on WO3 nanoflowers to form a WOM heterojunction, which improved the photocatalytic performance and molecular oxygen activation ability of the catalyst. This novel WOM heterojunction exhibited excellent photoactivity for degrading rhodamine B (RhB), photocatalytic water splitting ability and molecular oxygen activation ability under sunlight irradiation. Among all the samples, WOM83% could degrade 98% of 30 ppm RhB in 40 min. Meanwhile, WOM83% exhibited the highest hydrogen generation rate (4214.2 μmol h−1 g−1) and the strongest TMB oxidation capacity, and can generate 2.23 μmol of ·O2− in 50 min. The enhanced photocatalytic performance via heterojunction construction may be attributed to these following reasons: (i) higher light absorption achieved by the MoO3−x and WO3 composite; (ii) the matched energy band gap of MoO3−x and WO3 led to higher photogenerated carrier mobility; (iii) MoO3−x with oxygen vacancies as electron traps suppressed the photogenerated carrier recombination; (iv) enhanced molecular oxygen activation ability of the WOM heterojunction, such as the production of ·O2−. The measurements for TMB photo-oxidation and ·O2− showed excellent molecular oxygen activation ability of WOM heterojunctions. Finally, a possible photocatalytic mechanism was proposed. This study provided a viable option for the application of materials with oxygen vacancies to remove pollutants and improve molecular oxygen activation ability.
Shuwen Zhu,Huiqing Fan,Yao Su,Yongbo Fan,Weijia Wang
Real-time monitoring of triethylamine (TEA) is essential for environmental safety and various applications in daily life. However, TEA gas sensors still encounter specific technical challenges, such as high operating temperatures and insufficient sensitivity. In this study, in order to reduce the operating temperature and improve sensitivity, WO 3 -MoO 3 (WMo) n-n heterojunctions were synthesized via calcination and subsequent solvothermal method, in which WO 3 tightly bound to the MoO 3 nanobelt surface. The resulting heterojunction demonstrated excellent TEA sensing performance. The optimized gas sensor achieved a high response of 627.28 to 20 ppm TEA at a low operating temperature (100 °C). In addition, the device exhibited strong selectivity and stability. These improvements in gas sensing performance were attributed to the formation of n-n heterojunction between MoO 3 and WO 3 , as well as the surface gas sensing reaction of oxygen species facilitated by oxygen vacancies at the heterojunction interface. This study can be applied to the design of novel n-n type metal oxide heterojunction materials for the application of low-temperature high-sensitivity TEA sensors.
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